The present invention generally relates to methods for monitoring and controlling multiple devices connected to a common power line, and more particularly to a DC power line communication system. The invention has particular application to monitoring and controlling lighting elements or fixtures of a lighting system over a DC power buss to which the lighting elements or fixtures are connected. However, it will be appreciated that the invention will have other applications where it is desired to monitor and/or control multiple devices powered from a common low voltage DC power line.
Power line communication (PLC) systems used for controlling multiple components of a closed system, such as the lighting elements of a lighting system or fixture, are well known. Such systems allow inter-component communications to be achieved without bulky wiring and complicated configurations. However, such systems generally are not easily serviced when addressable components of the system need to be replaced or exchanged. They also have another disadvantage, in that communication nodes used with the lighting elements typically involve relatively costly parts that, when multiplied over many addressable components, can add tremendous cost to the system. The present invention allows for the implementation of a DC power line communication system with relatively inexpensive components and one that provides for an auto-commissioning capability during the power up which eliminates operational drawbacks of conventional PLC systems. The PLC system in accordance with the invention can be implemented in conventional DC two-wire wiring configurations without the need to add extra communication lines, and it allows the system-connected devices to be easily serviced or replaced.